Rubber valve stem for inner tubes and the like



Jan. 3, 1939. G. w. BECKER RUBBER VALVE STEM FOR INNER TUBES AND THE LIKE Original Filed Oct. l1, 1933 3 Sheets-Sheet' l l Snventor eolfsde Qe l* ttorneg .m f////////A/////7//// lia Jan. 3, 1939. l G; w. BECKER 2,142,708

' RUBBER VALVE STEM FOR INNER TUBES AND THE LIKE Original Filed 061;. llJ 1933 3 Sheets-Sheet 2 A El! lilllElllWhL Jan. 3, 1939. G, W BECKER 2,142,708

RUBBER VALVE STEM FOR INNER r.IUBES AD THE LIKE Original Filed Oct. ll, 1933 5 Sheets-Sheet 3` (It crneg Patented Jan. 3, 1939 UNITED STATES PATENT oFFIcEA RUBBER. VALVE STEM Foa INNER TUBES AND THE LIKE Original application October .11, 1933, Serial No. 693,114. Divided and this application March 4, 1937, Serial No. 128,970

4 Claims.

This invention relates to rubber valve stems for use.` on inner tubes forpneumatic tires and for use on similar inflatable rubber articles.

The chief objects of the invention are to provide a construction in which the valve stem may not readily be torn from the tube; and a construction which positively prevents leakage of air at the connection between valve stem and tube. A further object is to provide an improved rubber valve stem which may be vulcanized to an inner tube to provide a smooth contour at the junction for eliminating any sharp shoulders or steppeddown portion between the valve stem and tube. Still another object is to provide a valve stem structure which will prevent the ingress of dirt and water to the interior of the tire rim through the valve stem hole. Other objects of the invention will be manifest.

This application is a division of my co-pending 'application Serial No. 693,114, led October/,11, 1933, now Patent Number 2,120,346, June 14, 1938.

Of the accompanying drawings:

Figure 1 is a side elevation of a rubber valve stem, in its preferred form, before it is incorporated in an inner tube;

Figure 2 is a plan view thereof;

Figure 3 is a plan View of a portion of the outer surface of an inner tube, and a rubber valve stem built into the wall thereof;

Figure 4 is a section on ure 3;

Figure 5 is a fragmentary transverse section of a vulcanizing mold, and the improved valve stem and adjacent portionof an inner tube therein;

Figure 6 is a transverse section through a finished inner tube adjacent the valve stem thereof, the latter being shown in elevation;

Figure '7 is a section on the line 1 1 of Figure 6;

Figurep is a fragmentary transverse section through a pneumatic tire and a rim in which it is mounted, there being an improved inner tube in the tire;

Figure 9 is a view similar to Figure 8 showing the arrangement with an inner tube having a non-radial valve stem; and

Figures 10 and 11 are side elevations of rubber valve stems) of modified form.

Referring to the drawings, the rubber valve stem I shown therein is substantially cylindrical throughout its length, being provided only with sumcient taper or draft to permit easy removal from the mold in which it is made. At its base it is formed with an integral ange II preferably of rhombus or` diamond shape, said ange having the line 4-4 of Figits marginal portion tapered or beveled substantially to a feather edge. At the juncture of the stem I0 and .iiange II is an annular shoulder or boss I2 that is concentric with the stem and of somewhat larger diameter than the latter, there being a substantial fillet or radius I3 where the stem joins said shoulder. 'I 'he fillet I3 may be 'formed with a circumferential series of short,

longitudinally disposed, shallow grooves I4, I4 if desired. The Valve stem structure is partly or completely vulcanized before it is incorporated in a tube. Molded into the stem I0 and projecting from the end thereof remote from the flange II is the usual tubular metal insert I for receiving the valve mechanism of the structure.

In order to bring out the advantages of the present valve stern construction, further disclosure is made of the manner of incorporating same with an article on which it is to be used, for example, an inner tube for pneumatic tires.

The valve stem structure is mounted in an inner tube before the latter is vulcanized, and usually after it is spliced to annular form, a portion of a tube wall being shown at I6. The flange II of the valve stem is buffed on both sides, the outer surface of the tube about the inflation aperture II therein is cleaned and made tacky with suitable rubber solvent, and the valve stem iiange applied and adhered to said cleaned portion, the long axis of the flange being disposed longitudinally of the tube, and the axial passage in the valve stem being aligned with the aperture II of the tube. Then a plurality of axially apertured,

rhombus-shaped pieces of unvulcanized rubber I8, I9 and 20 respectively are superposed upon the iiange II so as to overlie the margins thereof and-extend onto the surface of the tube, the superposed pieces being treated with rubber solvent so as to adhere to each other and to the flange and tube. The pieces I8, I9 and 20 are relatively thin and of different sizes and are assembled so that their margins are in stepped or spaced relation to each other as shown. The axial apertures in said pieces are of the same diameter as the shoulder or boss I2 of the valve stem structure, and the thickness of the assembled pieces is substantially the same as the height of said shoulder so that the latter is` concealed in the assembled structure, as is most clearly shown in Figure 4.

'I'he assembled tube is then vulcanized in a mold under heat and internal pressure in the usual manner, a portion of the mold being shown in Figure 5. The mold shown comprises respective upper and lower mold sections l22, 23 that have their meeting edges offset fromltvhe-central the valve stem so that but little of the latter is in contact with the block 25 during vulcanization of the tube, whereby overcuring of the stem is avoided. The inner end of the aperture 26 is rounded as at 21, the arrangement being such that during vulcanization the fillet I3 of the valve stem engages rounded portion 21, 'and the juncture of shoulder I2 and pieces I8, .I3 and 20 engages the inner' face of block 25 with the result that there is no flow of the rubber from said pieces past the shoulder I2, and a neat and efcient joint is produced. The nished inner tube and valve assembly is shown in section in Figures 6 and 'Z-wherein it will be seen that the overlying pieces I8, I9 and 20 have coalesced with each other and with the wall of the tube I6 so that the valve stem flange II ris embeddedl centrally in the tube wall, and is f'lrmly vulcanized thereto sol as to form a unitary structure.

Preferably the interior surface of the tube I6 is treated with a composition 28 that seals the pores in the rubber of the tube and prevents the seepage of air therethrough. Such a composition is disclosed in the patent to Calvert, U. S. Patent No. 1,846,790.

In Figure 8 the inner tube is shown as it appears in inflated condition in a tire casing 30 mounted on a drop center rim 3|. The latter is formed with an aperture 32 through which the valve stem I 0 extends, said aperture being of such size that the inner corner thereof is engaged by the fillet I3 at the base of the valve stem whereby an effective seal is formed to prevent the entry, of dirt and grit through said aperture. The grooves I4 in the valve stem permit the escape of entrapped air from between the inner tube and the rim, past the seal formed at the rim aperture 32.

The invention provides a strong and durable tube construction that will not leak at the juncture of valve stem and tube, and which achieves the several objects set forth in the foregoing statement of objects.

In Figure 9 the inner tube 34 is shown in inflated condition in a tire casing 3l! that is mounted upon a drop center rim 35 that has a valve stem aperture 36 formed in one of the sidewalls of its central peripheral well or groove. The valve stem 31.of the inner tube is relatively short, and is disposed at an angle to the plane of the tube, but otherwise the 'tube is of the same costru'ction as that previously described. The valve stem 31 as shown alone in Figure 11- is formed with the. shoulder 43 and illlet 44.

The valve stern 39, Figure 10, lacks the shoulder or boss at its base, but it includes a relatively large llet at the juncture of stem and base ange 4I.

Other modii'lcations may be resorted to without departing from the spirit of the invention or the scope of the appended claims, which are not limited wholly to the specific construction shown or exact procedure described.

What is claimed is:

1. An inner tube structure comprising an endless rubber tube and a rubber valve stem, the latter being. formedat one end with an annular concentric shoulder and a relatively large, integral flange extending beyond said shoulder, said flange being embedded in the wall of the tube to the depth of said shoulder, the tube wall being ilush with the top of the shoulder.

2. An inner tube structure comprising an endless rubber tube and a rubber valve stem, the latter being formed at one end with a concentric shoulder and a base flange, the stem merging with the shoulder through a relatively large flllet and the latter being formed with a plurality of longitudinally disposed shallow grooves that extend substantially to the perimeter 'of the shoulder, the tube wall overlying the said base ilange and laterally abutting said shoulder and being ilush with the top thereof, the shoulder constif tuting a stop that prevents the tube-wall material from flowing into the said grooves during vulcanization of the tube.

3. A flexible rubber valve stem structure for inner tubes, said structure comprising a rubber stern having a metal insert in one end portion thereof, the opposite end of the stem being formed with an integral terminal base ange, and a relatively low cylindrical shoulder formed concentrically about the stem perpendicular to said base ilange, there being a relatively large llet extending from the top of the shoulder to the stem.

4. A rubber covered metal valve stem comprising a relatively large rubber Ilange formed integral with one end of the stem, there being a relatively low cylindrical shoulder formed concentrically of the stem and integral with the flange and stem at the junctureof the latter with the said flange, said shoulder being perpendicular to the latter and being of substantially greater diameter than the stem.

GEORGE W. BECKER. 

